Burglar or fire alarm.



' G. SPITZ.

BURGLAR 0R FIRE ALARM.

APPLlCATlON FILED APR. 11, 1912.

1,140,081 Patented May 18, 1915.

Witness es THE NORRIS PETERS 60.. FHOTOYLITHOUYWASHINGTUN, D. C

f9 @AWQ GUSTAV SPITZ, OF BRIl'NN, AUSTRIA-HUN GARY.

BURGLAR OR FIRE ALARM.

Specification of Letters Patent.

Patented May 18, 1915.

Application filed April 17, 1912. Serial No. 691,451.

T all whom it may concern Be it known that I, GUsTAv Srrrz, manager, citizen of Austria, residing at Briinn, Moravia, in the Empire of Austria-Hungary, have invented a new and useful Bur glar or. Fire Alarm; and I do hereby declare the following to be a full, clear, and exact description of the same.

The subject-matter of my invention is a burglar or fire alarm based on producing in the room or chamber to be secured a constant diflerence of pressure, independent of temperature, height of the barometer and leaks, as compared with the atmosphere, and causing an alarm to be sounded when this difference of pressure disappears.

In the accompanying drawing, showing by way of example, two of many possible embodiments of the invention, Figure 1 is a diagrammatic View showing a room or inclosure, with one form of the invention applied thereto; Fig. 2 is a diagrammatic vertical sectional view of another form of the invention, and Fig. 3 is a vertical section taken at right angles to that of Fig. 2.

Referring more particularly to Fig. 1 of the drawing, a fan 5 mounted in the wall of the room or chamber a to be protected produces in this chamber a difl'erence of pressure as compared with that of the outer atmosphere. The chamber a contains a vessel c which is partially filled with a liquid, 6. g. water, and is divided by a partition d into two compartments 0 and f communieating with one another, the partition being attached to the lid or cover 0 of the vessel and extending nearly to the bottom.

The compartment 6 is connected with the atmosphere by a pipe 9 which opens into the vessel 0 above the level of the water, while in the compartment f communicating through a hole 0 with the chamber a is inserted a float h which is pivotally connected to the lever 70 by means of the rod 7: passing through the hole 0 This lever is is mounted to rock on the support m. The contact lever n, pivotally connected with the rod 2', is fulcrumed in the support m and owing to the difference of pressure which exists in the chamber a and raises the level of the water in the compartment 7 this lever 72. is kept in such a position that the working current contact 0 is open and the closed circuit contact 0 closed.

Whenever an attempt is made forcibly to enter into the chamber a an opening must of course be made through which more air will enter than the fan can remove for producing that rarefaction to which the apparatus is adjusted. The difference of air pressure consequently becomes less or is entirely negatived. The float h sinks, the contact 0 is closed and the closed circuit] contact 0 which is provided only for the sake of safety and may be omitted, is opened so that thebells 9 arranged at suitable places are sounded. The same operation takes place when the fan 6 is stopped working for any cause.

The cover of the vessel 0 is provided with a small hole 0 which communicates with the compartment 6, so that the float hi can sink and the signals sound when air is unauthorizedly prevented from entering through the pipe 9. In this event, the same pressure and height of water-level will of course exist in the two compartments e and f of the vessel 5, so that the float occupies a lower position than formerly.

The described apparatus may be erected outside the chamber or room to be protected, when its compartment 6 will be connected with the chamber a by a pipe. In this event it operates in the reverse manner, 71. e. the water-level is normally higher in the compartment e and lower in the compartment f, and when the pressure is equalized the float rises and causes the contacts to be operated in the reverse manner.

The fan I) may compress the air in the chamber or room a if desired and bring about the same action as described above when the contacts are correspondingly arranged.

In order to prevent its being forgotten to place the apparatus into its working position when leaving and closing the room or chamber to be protected the electric circuit may be connected in a suitable manner with the lock of the door.

If the above described apparatus is to be employed as a fire-alarm a hole 1" will be provided in the ceiling of the room a or near the same and closed with a waxed sheet 8 or a plate composed of a readily fusible alloy. This sheet or plate will melt owing to the high temperature caused by a fire and allow the air to enter, whereby the existing difference of pressure is negatived.

The above described apparatus may be varied according to the Figs. 2 and 3 in such a manner, that a box t with a cover u in form of a diaphragm or porous membrane from leather or the like, replaces the liquid and the float h and renders the partition cZ superfluous. The rod i With the contact lever n is directly attached to the diaphragm a. By the difference of pressure in the box and the room a the diaphragm is raised and the lever n is kept in such a position, that the working current contact 0 is open and the closed circuit contact 0 closed. The air entering continuously through the pipe 9 in the boX passes in consequence of the porosity of the diaphragm gradually through the latter.

I claim 1. In a circuit controlling apparatus, the combination of, a closed container partly filled with liquid and comprising two communicating compartments, one of which is adapted to communicate with the outside air; a float in the other compartment; a contact balance-lever outside of the container and connected to the float; and an alarm circuit adapted to be closed or opened by the balance-lever.

2. An apparatus for controlling the closing of the circuit in burglar and fire alarms, consisting of a closed container partly filled with fluid and arranged in the room to be protected and comprising two compart ments, one of which is connected with the outside atmosphere; a float in the other compartment; an alarm circuit; and a contact lever constructed in the shape of a scale beam and operatively connected to the float and adapted to close or break said circuit according to the position of the float.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

GUSTAV SPITZ,

Witnesses:

MoRrrz SCHMOLKA, RUDoLr WARTooHA.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

